1. Field of the Invention
Example embodiments of the present invention relate to an analyzing chamber and a mass analyzer including the same. In particular, example embodiments of the present invention relate to an analyzing chamber including a leakage ion beam detector for detecting a leak in a guide protecting a sidewall of the chamber, and a mass analyzer including the same.
2. Description of the Related Art
Generally, semiconductor devices are manufactured by a series of unit processes including, for example, a photolithography process, an etching process, a diffusion process, an ion implantation process, a polishing process, cleaning and drying processes, etc. One or more of the processes may be selectively and repeatedly performed on a semiconductor substrate such as a wafer, for example. Among the above unit processes, the ion implantation and the diffusion processes may affect the electrical characteristics of the wafer the most.
In an ion implantation process, a sufficient energy to penetrate a surface of the wafer may be applied to a plurality of ions and the ions may be implanted into the surface of a wafer at a depth. A conventional ion implantation process may be used to facilitate density control of the impurities implanted into the wafer and to accurately control the implantation depth of the impurities. Accordingly, an ion implantation process may be widely used for manufacturing a highly integrated semiconductor device.
FIG. 1 is a view schematically illustrating a structure of a conventional ion implanter.
Referring to FIG. 1, a conventional ion implanter 90 may include an ion source unit 10, a beam line assembly 20, an end station unit 30, a driving unit 50 and a control unit 40. In the ion source unit 10, an impurity gas may be ionized into a plurality of impurity ions and a high energy may be applied to the impurity ions to generate an ion beam. The beam line assembly 20 may guide the ion beam from the ion source unit 10 to a destination through a predetermined path. The end station unit 30 may accurately position a target wafer, and the driving unit 50 may drive the target wafer. The control unit 40 may systematically control the ion source unit 10, the beam line assembly 20, the end station unit 30 and the driving unit 50. Each of the above units may be connected to the control unit through a data line 7 and a control line 8, for example.
The beam line assembly 20 may include a mass analyzer 23, a gate valve 21, an ion accelerator 25 and a deflection unit 27. The mass analyzer 23 may extract ions from an ion beam passing through a magnetic field based on a mass/charge ratio of each ion. The gate valve 21 may be interposed between the ion source unit 10 and the mass analyzer 23 and may selectively allow a generated ion beam to travel into the mass analyzer 23. The ion accelerator 25 may accelerate the extracted ions from the mass analyzer 23, and the deflection unit 27 may substantially uniformly scan the accelerated ions onto the wafer.
Impurity material may be supplied to the ion source unit 10 of the ion implanter 90 in a gaseous state and may be ionized into a plurality of charged particles. A high energy may be applied to the charged particles in the ion source unit 10 so that the charged particles leave the ion source unit 10 as an ion beam moving at a high velocity. Then, the gate valve 21 may be opened and desired ions may be selected in and pass through the mass analyzer 23. The desired ions may be implanted into a top surface of the wafer after traveling through the ion-accelerator 25 and the deflection unit 27. The wafer may be positioned in the end station unit 30.
FIG. 2A is a perspective view illustrating a conventional mass analyzer shown in FIG. 1, and FIG. 2B is a plan view illustrating the conventional mass analyzer shown in FIG. 2A.
Referring to FIGS. 2A and 2B, a conventional mass analyzer 23 may include an analyzing chamber 23a for changing the direction of travel of the ion beam irradiated thereto, a shielding section 23b for protecting a sidewall of the analyzing chamber 23a from the high-energy ion beam and a magnet (not shown) installed in the analyzing chamber 23a and generating a magnetic field for extracting ions from the ion beam.
The analyzing chamber 23a may include an inlet I and an outlet E. The longitudinal direction of the inlet I may be different from the longitudinal direction of the outlet E. The ion beam may enter the analyzing chamber 23a through the inlet I and ions may be selected in the analyzing chamber 23a. Accordingly, only desired ions leave the analyzing chamber 23 through the outlet E in the longitudinal outlet direction, which may be different from the longitudinal inlet direction. In a conventional analyzing chamber 23a, the outlet longitudinal direction is perpendicular to the inlet longitudinal direction and thus, the conventional analyzing chamber 23a may have the shape of a capital letter ‘L’. Accordingly, in a conventional analyzing chamber 23a, the direction of travel of the ion beam may be perpendicularly changed in the analyzing chamber 23a. 
The shielding section 23b may be arranged on an inner sidewall of the analyzing chamber 23a and may prevent an ion beam from causing damage to the inner sidewall of the analyzing chamber 23a. The shielding section 23b may include a plurality of shield partitions, which may be individually inserted into a groove one by one such that all of the inner sidewall of the analyzing chamber 23a may be covered with the shielding section 23b. For example, the shielding section 23b may include graphite such as black lead, for example, so that the ion beam may be adsorbed onto the shielding section 23b. 
An ion beam entering the analyzing chamber 23a through the inlet I may be deflected, travel along an arc-shaped path R and leave the analyzing chamber 23a through the outlet E based on a direction of a magnetic field generated by the magnet. Some of the charged particles, each of which may have a mass smaller than that of the desired ions, may travel along a path L in the analyzing chamber 23 and thus, may be adsorbed onto the shielding section 23b. Further, other charged particles, each of which may have a mass greater than that of the desired ions, may travel along a path H in the analyzing chamber 23 and thus, may be adsorbed onto the shielding section 23b. Accordingly, only the desired ions leave the analyzing chamber 23a. 
Accordingly, as the conventional mass analyzer 23 is repeatedly operated, the graphite of the shielding section 23b may gradually wear away due to collisions with the ion beam and a hole may be generated on an inner surface of the shielding section 23b. As a result, the inner sidewall of the analyzing chamber 23 may be partially exposed through the hole, and the ion beam may be irradiated onto the inner sidewall of the analyzing chamber 23 and may cause damage to the inner sidewall of the analyzing chamber 23. The damage to the inner sidewall of the analyzing chamber 23 may deteriorate the vacuum degree of the analyzing chamber 23a so that the desired ions can no longer be accurately extracted from the damaged conventional mass analyzer 23. If the shield partitions are not accurately arranged on the inner sidewall of the analyzing chamber 23a and a chink 27 is generated between neighboring shield partitions, the inner sidewall of the analyzing chamber 23a may not be completely covered with the shield partitions and the inner sidewall of the analyzing chamber 23a may be exposed to an ion beam. Accordingly, damage 28 may be caused to the inner sidewall of the analyzing chamber 23.
FIG. 3 is a view illustrating a chink between neighboring shield partitions in a conventional analyzing chamber, and FIG. 4 is a view illustrating damage to the inner sidewall of the analyzing chamber, which may be caused by an ion beam leaking through the chink shown in FIG. 3.